From 05bfebed2657cc1d032c9796efd9041bfbdc881c Mon Sep 17 00:00:00 2001 From: Robert Mader Date: Sun, 12 Oct 2025 16:20:52 +0200 Subject: [PATCH] pipeline: simple: Allow buffer counts from 1 to 32 While a default value of 4 buffers appears to be a good default that is used by other pipelines as well, allowing both higher and lower values can be desirable, notably for: 1. Video encoding, e.g. encoding multiple buffers in parallel. 2. Clients requesting a single buffer - e.g. in multi-stream scenarios. Thus allow buffer counts between 1 and 32 buffers - following the default maximum from vb2 core - while keeping the default to the previous 4. While on it mark the config as adjusted when appropriate. Signed-off-by: Robert Mader Reviewed-by: Milan Zamazal Reviewed-by: Kieran Bingham Signed-off-by: Kieran Bingham --- src/libcamera/pipeline/simple/simple.cpp | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp index 6a2ffe62..dec9f651 100644 --- a/src/libcamera/pipeline/simple/simple.cpp +++ b/src/libcamera/pipeline/simple/simple.cpp @@ -378,6 +378,9 @@ public: const Transform &combinedTransform() const { return combinedTransform_; } private: + static constexpr unsigned int kNumBuffersDefault = 4; + static constexpr unsigned int kNumBuffersMax = 32; + /* * The SimpleCameraData instance is guaranteed to be valid as long as * the corresponding Camera instance is valid. In order to borrow a @@ -1240,7 +1243,7 @@ CameraConfiguration::Status SimpleCameraConfiguration::validate() cfg.size != pipeConfig_->captureSize) needConversion_ = true; - /* Set the stride, frameSize and bufferCount. */ + /* Set the stride and frameSize. */ if (needConversion_) { std::tie(cfg.stride, cfg.frameSize) = data_->converter_ @@ -1263,7 +1266,18 @@ CameraConfiguration::Status SimpleCameraConfiguration::validate() cfg.frameSize = format.planes[0].size; } - cfg.bufferCount = 4; + const auto bufferCount = cfg.bufferCount; + if (bufferCount <= 0) + cfg.bufferCount = kNumBuffersDefault; + else if (bufferCount > kNumBuffersMax) + cfg.bufferCount = kNumBuffersMax; + + if (cfg.bufferCount != bufferCount) { + LOG(SimplePipeline, Debug) + << "Adjusting bufferCount from " << bufferCount + << " to " << cfg.bufferCount; + status = Adjusted; + } } return status;